[0023] Example 1: The production line is installed in accordance with the technical requirements of the semi-dry artificial sand making process in Figure 1 and Figure 2.
[0024]The semi-dry sand making process system is mainly composed of coarse crushing 1, semi-finished product silo 2, pre-screening workshop spray system 3, medium crushing workshop 4, first screening workshop spray system 8, 1# transfer bin 17, one It is composed of water adding system in the fine crushing workshop, the second screening workshop 14, the second fine crushing workshop 15, the belt conveyor and the sand water recovery system; the automatic control technology is mainly composed of the automatic control of the artificial sand fineness modulus, the automatic control of the stone powder content and the finished product The automatic control of sand moisture content consists of three parts. The system equipment consists of a belt conveyor load detection device 20, a sand moisture detector 19, an electric adjustable feeding device for the transfer bin, a wind control device and a computer for the powder raising system controlled by the stone powder content It is composed of control host computer 23. The semi-dry sand making process requires less one-time investment, and the quality of the finished products meets the quality requirements of concrete.
[0025] The intelligent control technology of the production process mainly starts from the sand making material source enters the transfer bin, and starts the fine crushing process, and mainly controls the moisture content, fineness modulus and stone powder content of semi-dry artificial sand.
[0026] The sand making material source is processed by a vertical crusher, and the sand making machine can be adjusted to low speed (rotor linear speed <58m/s) and high speed (rotor linear speed>72m/s) combined sand making. The linear speed of the rotor of the vertical shaft sand making machine can be automatically adjusted according to the powder content of the semi-finished sand produced. The low speed of the rotor of the sand making machine increases the output, and the high speed of the rotor increases the stone powder content, and the overall sand production rate is improved. The system consists of a low-speed machine to form a primary fine crushing (sand making) workshop, and a high-speed machine to form a secondary fine crushing (silt) workshop. According to the output of the sand making machine, the feed volume of the circular vibrating screen and the high frequency vibrating screen is reasonably controlled. The circular vibrating screen 21 and the high frequency vibrating screen 22 are both installed with 5mm and 3mm screens. After screening, the 3mm~5mm part of the material enters the secondary fine crushing workshop for high-speed crushing. In order to meet the peak demand of concrete pouring, the vertical sand making machine can simultaneously use low-speed production of artificial sand and gravel during the peak period to increase the output, the adjustment of the artificial sand fineness modulus and insufficient stone powder are integrated from the sand produced by the silt workshop Deployment. The fineness modulus of artificial sand is controlled between FM=2.4~2.8, and the content of stone powder is controlled between 16%~21%. among them:
[0027] (1) Vertical shaft sand making machine (rotor low speed) processes aggregates of 40mm~3mm of sand making material, and the semi-finished sand produced is sieved with a mesh aperture of 3×10mm, and the sand fineness modulus FM is 3.0~3.3 Among them, the stone powder content is between 13% and 16%, and the moisture content is between 3% and 4.5%.
[0028] (2) The sand made by the vertical shaft sand making machine (high speed rotor) is 5mm~3mm aggregate selected by sieving, and the semi-finished sand produced is sieved with a screen aperture of 4×10mm, and the sand fineness modulus Between 2.2 and 2.4, the stone powder content is between 28% and 32%, and the moisture content is between 3% and 4.5%.
[0029] (3) Aggregate of 40mm~3mm of sand making material adopts sand produced by the rotor of sand making machine at low speed and aggregate of grain size 5mm~3mm adopts sand produced by the rotor of sand making machine at high speed, which is obtained after synthesis according to the ratio of 4:1 For the finished sand, the fineness modulus of the finished sand is between 2.4 and 2.8, the stone powder content is between 17% and 21%, and the moisture content is between 3% and 4.5%.
[0030] Implementation mode of intelligent control technology for semi-dry artificial sand:
[0031] (1) Automatic control of moisture content of finished sand
[0032] When the system is in production, the feed flow rate and moisture content of the sand making machine's material source are measured by the load detection device on the feed belt conveyor to adjust the water supply volume of the electric water supply ball valve, so as to achieve the best moisture content control of the system's finished sand.
[0033] In the production process, the source of the sand making material is automatically detected by the moisture content detector and then enters the sand making machine for crushing. The main equipment for controlling the moisture content includes an electric ball valve 29 and a moisture content detector 19. The source of sand making material is generally 3mm-40mm aggregate, and the water content is relatively low. Specifically, the microwave-type sand moisture content tester installed on the feeding belt conveyor in the sand making workshop measures the moisture content of the material source in the sand workshop. During production, the water volume of the pressure regulating water pump should be adjusted according to the flow rate of the sand machine material source. , To achieve the best moisture content control of the sand making material source. The information detected by the automatic water content detector is automatically fed back to the upper computer of the automatic control system. According to the information obtained by the upper computer, the water content of the sand making source is adjusted and controlled automatically by the electric ball valve controller. Adjust to adjust the water output.
[0034] (2) Automatic control of fineness modulus of artificial sand
[0035] The automatic control of the artificial sand fineness modulus of the semi-dry sand making process is mainly based on the characteristics of the semi-dry sand making process. During the system debugging and operation, find out the amount of feed in the sand making workshop and the particles screened in the sand screen workshop. The relative relationship between the output quantity of the diameter section, the feed quantity of the silt workshop and the sand fineness modulus, the fineness modulus of the finished aggregate can be adjusted by changing the feed quantity of the silt workshop. The main process of the automatic control of the artificial sand fineness modulus is: when the semi-dry sand making system is operating normally and is operating relative to a certain fixed processing capacity, the feeding capacity of the sand making workshop and the silt sand workshop is always the same. Stable proportional relationship. At this time, the fineness modulus FM of the finished sand produced by the semi-dry sand making process is between 2.4 and 2.8; when the processing capacity of the system increases or decreases according to the production needs, the sand making workshop will provide The amount of material has also increased or decreased accordingly. The load detection device installed on the feeding belt conveyor in the sand making workshop senses this change in time, and transmits the change to the upper computer of the semi-dry sand making process automation control system, and the automatic control system After receiving the detection signal of this situation, a control command is issued to adjust the feeding amount of the silt sand workshop, so that the fineness modulus of the finished sand produced by the system runs stably between 2.4 and 2.8.
[0036] The control positions of the artificial sand fineness modulus and stone powder content are mainly the feed volume of the fine crushing sand making machine, the sand sieving 3mm~5mm sand volume and the feed of the secondary fine crushing (silt sand) workshop sand making machine Quantity (3mm~5mm). Automatic control mainly includes: install the automatic detection device of fineness modulus on the tape entering the finished product silo, the discharge tape of the secondary fine (silt) workshop, and the discharge tape of the sand screening workshop, respectively, and feedback of the detected information To the upper computer, the upper computer adjusts the feed volume of the fine crushing sand making machine, the linear speed of the sand making machine rotor, and the feed volume of the silt workshop according to the information obtained. It can be adjusted jointly or independently to make production The fineness modulus and stone powder content of the sand reach the optimal standard for concrete sand.
[0037] (3) Automatic control of stone powder content
[0038] In view of the case where the material source is limestone, the semi-dry sand making process can make the system's sand production relatively stable between 16% and 22%, and can meet the requirements of normal concrete and roller compacted concrete for the finished sand powder content. When the feed volume of the system sand making workshop and silt workshop changes greatly, resulting in an increase in the content of the finished sand and gravel powder, and in order to meet the environmental protection requirements of the system dust emission, the system is equipped with a stone powder separation and dust collection device through which the finished product is realized Separation of sand and stone powder.
[0039] The stone powder separation and dust collection device consists of a powder raising system, a negative pressure dust suction system, a gas dust separation system and a pipeline system. The powder raising system is mainly composed of an axial flow fan and its governor, which is responsible for the separation of sand and stone powder, and the other three systems are responsible for the transportation of dust and the separation of gas and dust.
[0040] When the system changes greatly due to the feeding volume of the first-level fine crushing sand making workshop and the second-level fine crushing (silt sand) workshop, the automatic control system will issue the order from the host computer according to the load conditions of the feeding belt conveyors in the two workshops. The instruction is to adjust the air supply intensity of the axial fan by controlling the speed governor of the dust-raising system of the stone powder separation and dust collection device, thereby controlling and adjusting the amount of powder raised by the system, and changing the powder content of the finished sand; it has been separated from the sand and raised The generated dust is sucked into the air-dust separation system by the negative pressure suction system through the pipeline system, and the separation of gas and dust is completed by it. The separated excess stone powder is treated by wet processing, and it is wetted into a jelly and used as a waste The material was transported away.
